Nature Physics, Published online: 06 November 2025; doi:10.1038/s41567-025-03067-5
In a heavy-fermion material, hybridization of conduction electrons and electrons in partially filled core-levels enhances the mass of charge carriers. Now, experiments using a two-dimensional heavy-fermion material show that the hybridization can be extremely anisotropic, with the result that the effective mass of charge carriers is direction-dependent.
